Threaded bolts of all types, including rods, bent and headed bolts, are manufactured with either rolled threads or cut threads. Designers and contractors will notice advantages and disadvantages to both types. Misconceptions abound as well, and your fastener distributor is an excellent source of advice, helping you to order the right bolt for your application.
What Are Cut Thread Bolts?
There is more demand for cut threads, made by cutting away or removing the actual metal from a round steel bar. This type of bolt begins with a rod of the same diameter – for a 1-inch bolt the manufacturer cuts threads from a 1-inch rod.
Cut thread bolts come in a wide range of lengths and diameters, and meet all specifications. They also take longer to manufacture and create more waste, resulting in a higher cost. You may be wiser to opt for rolled threads at a lower price, although some diameters and thread lengths are only available in cut threads.
What Are Rolled Thread Bolts?
Rolled thread bolts are manufactured by extrusion, with round bars pressed through dies to displace the steel and form threads. Starting with a slightly smaller bar, the manufacturing process creates a larger bolt –a 1-inch bolt is manufactured from a 0.912-inch bar.
This manufacturing process is more efficient than cutting threads, resulting in lower costs across the board. But you’ll also find these fasteners weigh less and do not provide the necessary strength for critical wood applications.
As a result of burnishing during the rolling process, rolled thread bolts appear smoother. And because they are cold worked, rolled thread bolts hold up well during the handling process.
Certain specifications, namely A490 as well as A325, are not available in rolled thread designs. These specifications call for a full bodied fastener with cut threads. Your fastener distributor will often have a limited supply of rolled thread bolts, with a maximum diameter and thread length.
Depending on your application, budget and specifications, choosing between cut thread bolts and rolled thread bolts may be a confusing process. Both provide strength and dependability when made from premium materials, and work well on a wide range of projects. Your fastener distributor is the best source for advice of which thread style is best for your application.
Started my career in the fastener world in 1969 at, Parker Kalon Corp. a NJ based screw manufacturer located in Clifton, NJ working in inventory control, scheduling secondary production and concluding there in purchasing. In 1971 I accepted a sales position at Star Stainless Screw Co., Totowa, NJ working in inside sales and later as an outside salesman, having a successful career at Star I had the desire with a friend to start our own fastener distribution company in 1980 named: Divspec, Kenilworth, NJ. This was a successful adventure but ended in 1985 with me starting Melfast in August 1985 and have stayed competitive and successful to date. Melfast serves the OEM market with approximately 400 accounts nationally.